Stents are used in a wide array of bodily vessels including coronary arteries, renal arteries, peripheral arteries including iliac arteries, arteries of the neck and cerebral arteries as well as in other body structures, including but not limited to arteries, veins, biliary ducts, urethras, fallopian tubes, bronchial tubes, the trachea, the esophagus and the prostate.
Stents are typically balloon-expandable, self-expanding or a hybrid of the two. Balloon expandable stents may be made from a wide array of biocompatible materials including, for example, stainless steel. Self-expanding stents may also be made from a wide range of materials including biocompatible shape-memory materials including metals and polymers. An example of a suitable shape-memory metal is Nitinol.
In spite of the myriad of stent designs, there remains a need for novel stent designs as the technology of stent delivery progresses and as stents are employed with increasing prevalence in a variety of regions of the body.
As an example of the former, with the ever-increasing demand for stents to treat bodily vessels, there has been a demand for more flexible and trackable stents and stent delivery systems. One of the most significant recent changes to the stent delivery system involves the use of thin-walled balloons. This change has resulted in earlier cone deployment of the balloon which creates an inclined plane resulting in an inward axial force to the stent. The inward force, in turn, results in increased foreshortening of the stent upon deployment. Although a number of stents have been developed that are said to resist foreshortening, novel stent designs that generally resist foreshortening and in particular resist foreshortening when delivered on the newer thin walled balloons, are desirable.
As an example of the latter, in the area of aneurysm stenting, it is desirable for the stent to have relatively low radial strength to avoid dilating and rupturing the aneurysm. Standard techniques for reducing radial strength, however, typically result in stents which are not visible under fluoroscopy without the addition of radiopaque materials to the stent. The addition of radiopaque materials to the stent may alter the profile of the stent in the regions of the radiopaque material and may complicate the production of the stent. Thus, there is a need for novel aneurysm stents which are of low radial strength and which are visible under fluoroscopy.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
The invention in various of its embodiment is summarized below. Additional details of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.